A β-1,3-glucan is a polysaccharide having a β-1,3-bond of glucose as a main chain, and is present as a main structure in laminaran that is contained much in brown algae and the genus Laminaria, and in curdlan that is produced extracellularly by mutant strains of soil bacteria (Alcaligenes faecalis). Further, callose contained in cell walls of grains is also known.
β-1,3-glucans have a common characteristic of having a β-1,3-structure as a main chain, but depending on the origins thereof and the like, they are different from one another in terms of the presence/absence and the position of a branched side chain, the combination with a β-1,4-bond and a β-1,6-bond, the molecule size, and the like, thereby having different structures and properties, respectively.
A β-1,3-glucanase is an enzyme that hydrolyzes these β-1,3-glucans, and is used as an additive for fodders for improving body weight gains and feed demand ratios of domestic animals, as a physical property improving agent or a texture improving agent for confectionery, bread, and the like, and as an extraction efficiency improving agent for extracting yeast extract, and beer filtering efficiency improving agent, as well as for other various purposes.
There are β-1,3-glucanases that are derived from various origins, and have various substrate specificities, among which those exhibiting decomposition activity with respect to laminaran, curdlan, yeast cell walls, mycelium of lentinus edodes, pastoran, and the like, are known (Patent Documents 1 to 3).